The German Printed Patent No. 29 05 900 discloses a device for controlling the de-excitation time of electromagnetic devices, in particular electromagnetic injection valves in internal combustion engines, in which a circuit arrangement having an especially controllable output voltage is connected in series or in parallel to the electromagnetic device. In the case of known devices of this type, the inductive consumer is fed, for example, from a voltage source via a series-connected transistor, which is capable of being controlled by triggering means. A desired, fast current suppression when the transistor is switched off can be achieved by means of a Zener diode, which is wired parallel to the transistor, or rather by a transistor which is operated in a comparable manner with a Zener voltage, which is higher than the operating voltage at the moment of switch-off.
Instead of a separate suppressor device, such a transistor can also be directly provided with a so-called Zener bracketing and, thus, also be operated as a suppressor device. A disadvantage of this known device is that the suppressor device then also becomes unintentionally conductive and, in some instances, is unacceptably thermally stressed when the operating voltage in the case of a switched-off transistor becomes greater than the Zener voltage. This can occur, for example, when there is a so-called load-dump pulse on the operating-voltage line.